1. School of Geodesy and Geomatics, Wuhan University, Wuhan, China
2. School of Geodesy and Geomatics and the Key Laboratory of Geospace Environment and Geodesy, Ministry of Education, Wuhan University, Wuhan, China
3. Chinese Antarctic Center of Surveying and Mapping, Wuhan University, Wuhan, China
4. School of Earth Sciences and Engineering, Hohai University, Nanjing, China